Need Opinions for USB uPOV addition.
- May 2nd, 2011
- Posted in Uncategorized
- By rucalgary
- Write comment
I am working on a modified version of the uPOV hardware that uses the VUSB implementation for AVR microcontrollers to add USB capabilities so messages can be updated by someone without an ISP programmer…
Which leads me here…
I am currently thinking of 3 separate methods of going about this.
1. A CDC implemenation that basically creates a virtual com port that can be used to upload messages. – Seems to be the simplest, but requires special window driver.
2. A proprietary type of system that would require a driver on windows. – More complex than the CDC implementation and requires a small windows driver again. communication on linux boxes requires root or permissions modifications.
3. A HID version that would NOT require a driver for windows, but so far would require much more research on my part. – Seems to be quite complex would require much research.
What version do you think I should go with?
I would go with option 1. I deal with the VCP drivers all the time with no issues.
I’m guessing you will write some software to enter the message into, which will program the display? If so, I would go with whatever protocol enables to you do that super easily on all systems… which is probably the CDC and VCP route.
You could implement a programming scheme on-board though since you have the one button. A power switch and one momentary would be better though so you could do something like hold the button down when powering up to put into programming mode. Or press the button to cycle through letters/numbers/space/etc.. and when not in programming mode you can use the button to cycle through special modes (wipe/fade/brightness/different message banks… )
The computer seems like it would be easy to use to program your device… but maybe there is an even easier way… like if you can make V-USB act as a host and you can plug a keyboard directly into it, but I don’t think you can. It would probably be easier to just make a Cable Box remote control program the device over IR… or just the one button solution.
I have a one button clock and it doesn’t have a power switch… you just hold down the button when you plug it in for programming mode. And it cycles to the next digit after a period of time. You could do something similar with your button if it were wired to power AND a digital input, and then just hold it down when you slide the battery in for the first time. You can make it power on and off the device with long button presses normally, but the uC would have to latch power on for it to work. I’ve implemented power/enter buttons like this before in hand-held devices. Actually you could just hold down the one button for ON, and then continue to hold to enter program mode…. like a bluetooth headset sort of.
I like the idea of latching the power, but I’m afraid my cost is already getting up there… I am thinking about using the programming header and supplying a male jumper to connect one of the pins to ground…